Damage to wildlife and the physical environment can be minimized in the wake of an oil spill in a body of water if containment and recovery operations are started promptly after the spill. Accordingly, a specialized fleet of ships is currently being built in the United States for the sole purpose of responding quickly to oil spills. The ships will be stationed at strategic locations and will be maintained on a twenty four hour alert status so that they can be on the way to a spill in less than half an hour. In this manner, the oil spill problem will be handled along lines developed by the firefighting industry.
The new ships will be fitted, to some extent, with equipment already in use on existing spill-containment vessels. However, some items of existing equipment are inadequate to perform their intended functions. For example, the primary containment method is to vacuum up the spilled oil as it floats on the water. The oil thereby recovered is typically mixed with debris or flotsam; this flotsam includes liquids and solids which must be separated from one another before the recovered oil can be placed in a hold of the recovery ship or in containers for subsequent refining.
More specifically, the flotsam is generally collected on a large, perforated plate that acts as a strainer to separate the oil and solids in the flotsam. However, the solids are usually soaked with water and covered with oil; the oil clinging to the solids is not affected by the straining action of the perforated plate. Present practice is to discard the solids and oil coated thereon in fifty five gallon drums. Thus, the oil coated on the solids is lost. Moreover, the drum must then be treated as hazardous waste and disposed of as such. Obviously, the number of drums that are filled with oil-soaked solids at a major spill is large, and their disposal is a problem almost as troublesome as the spill itself.
There is a need for a flotsam separation device and method that enables a spill to be cleaned up with fewer drums and that salvages more oil from the spill as well, but the prior art, when considered as a whole at the time the present invention was made in accordance with the requirements of law, neither taught nor suggested to those of ordinary skill in this art how such a device and method could be provided. In fact, at the time the present invention was made, the conventional wisdom was that the status quo was satisfactory, and that liberal use of fifty five gallon drums and the loss or large quantities of oil would always be a fact of oil spill experience.